The present invention relates to a high-frequency treatment tool, which is inserted through a forceps channel of an endoscope and used for incision of mucous membranes and in vivo tissues inside a human body.
Generally, a high-frequency treatment tool for an endoscope is configured to have an electrically conductive operating wire arranged to be movable in an axial direction thereof in an electrically insulated flexible tube, which is inserted in a forceps channel of the endoscope. Further, a rod-like high-frequency electrode is connected to a tip end of the operating wire so that the high-frequency electrode can be protruded and retracted from a distal end of the flexible tube as the operating wire is advanced and retracted from a proximal end thereof.
In such a configuration, however, due to a security reason, such a high-frequency electrode is configured to be stabilized at a position wherein the operating wire is fully advanced toward the distal end and the electrode is extended to a maximum length thereof so that the length of the high-frequency electrode should not vary during an operation. Accordingly, a length of the high-frequency electrode to be protruded from the tip end of the flexible tube is not adjustable but fixed. Therefore, in some cases, the high-frequency electrode may be too short for an operation to incise in vivo tissue in a certain depth or may be too long for a certain incising operation.
In consideration of the above, a flexible tube provided with a length adaptor at the distal end of the flexible tube has been developed. An example of such an adaptor is disclosed in Japanese Patent Provisional Publication No. 2002-113016 (hereinafter, referred to as '016 publication). The adaptor disclosed in '016 publication is capable of extending and contracting in the axial direction. By coupling the length adaptor of which the length has been adjusted with the distal end of the flexible tube, the length of the high-frequency electrode to be protruded from the length adaptor can be adjusted depending on the incising operation.
With the adaptor, however, the configuration of the endoscope becomes more complicated, and a cost for the endoscope may be increased. Further, when the length of the high-frequency electrode to be protruded is changed, the treatment tool is required to be withdrawn from the forceps channel so that the adaptor can be detached from and re-attached to the distal end thereof. Thus, the operation to adjust the length of the high-frequency electrode has been complicated and rather troublesome.